Pal Prasanta, Bulgarevich Kirill, Hanaki Ryota, Kawabata Kohsuke, Takimiya Kazuo
RIKEN Center for Emergent Matter Science (CEMS) 2-1 Hirosawa, Wako Saitama 351-0198 Japan
Tohoku University Advanced Institute for Materials Research (AIMR) 2-1-1 Katahira, Aoba-ku Sendai Miyagi 980-8577 Japan.
Chem Sci. 2025 Jul 21. doi: 10.1039/d5sc03215f.
Controlling the crystal structures of polycyclic aromatic hydrocarbons (PAHs) by regioselective methyl chalcogenolation is an effective strategy for realizing superior molecular semiconductors showing ultrahigh mobility, as exemplified by methylthiolated pyrene and peropyrene. Following the strategy, we designed and synthesized 1,4,7,10-tetrakis(methylthio)coronene (MT-coronene) and 1,4,7,10-tetramethoxycoronene (MO-coronene) as potential candidates for high-performance molecular semiconductors. Since the coronene core is highly symmetric, the regioselective functionalization at the 1, 4, 7, and 10-positions seemed to be challenging, and thus, we tested two strategies for constructing such regio-selectively functionalized coronene derivatives: one was the direct functionalization of the parent coronene the iridium-catalyzed borylation reaction, and the other was the stepwise construction of the coronene core with functionalized naphthalene derivatives. Interestingly, the former was suitable for the synthesis of MT-coronene, whereas the latter was suitable for MO-coronene. The crystal structures of MT- and MO-coronene were significantly different from the γ-structure of their parent and were classified into the brickwork and the sandwich herringbone structure, respectively. In accordance with the brickwork crystal structures with isotropic but small intermolecular HOMO overlaps, the MT-coronene-based single-crystal field-effect transistors (SC-FETs) showed decent transistor responses with a carrier mobility of up to 0.5 cm V s. On the other hand, the SC-FETs of MO-coronene, the solid-state electronic structure of which was zero-dimensional due to the sandwich herringbone structure, were far inferior to those of MT-coronene. Based on the crystal structures and theoretical calculations on MT- and MO-coronene, we analyzed the tendency of the intermolecular interactions and intermolecular HOMO overlaps in the solid state, which explains the performances of the coronene system as molecular semiconductors. Furthermore, we compared the solid-state structures of a series of methylthiolated PAHs, pyrene, perylene, peropyrene, and coronene, to determine the differences in their performances as molecular semiconductors, which gave us new insights into the relationship between the molecular structure, packing, and electronic structure in the solid state, providing perspectives for superior molecular semiconductors.
通过区域选择性甲基硫属化来控制多环芳烃（PAHs）的晶体结构，是实现具有超高迁移率的优异分子半导体的有效策略，甲基硫醇化芘和全芘就是例证。按照这一策略，我们设计并合成了1,4,7,10-四（甲硫基）蔻（MT-蔻）和1,4,7,10-四甲氧基蔻（MO-蔻），作为高性能分子半导体的潜在候选物。由于蔻核具有高度对称性，在1、4、7和10位进行区域选择性官能化似乎具有挑战性，因此，我们测试了两种构建这种区域选择性官能化蔻衍生物的策略：一种是母体蔻的直接官能化——铱催化的硼化反应，另一种是用官能化萘衍生物逐步构建蔻核。有趣的是，前者适用于MT-蔻的合成，而后者适用于MO-蔻的合成。MT-蔻和MO-蔻的晶体结构与它们母体的γ-结构有显著不同，分别归类为砖砌结构和夹心人字形结构。与具有各向同性但分子间HOMO重叠较小的砖砌晶体结构一致，基于MT-蔻的单晶场效应晶体管（SC-FETs）表现出不错的晶体管响应，载流子迁移率高达0.5 cm V s。另一方面，MO-蔻的SC-FETs由于夹心人字形结构，其固态电子结构为零维，远不如MT-蔻的SC-FETs。基于对MT-蔻和MO-蔻的晶体结构及理论计算，我们分析了固态下分子间相互作用和分子间HOMO重叠的趋势，这解释了蔻体系作为分子半导体的性能。此外，我们比较了一系列甲基硫醇化PAHs、芘、苝、全芘和蔻的固态结构，以确定它们作为分子半导体的性能差异，这为我们提供了关于固态下分子结构、堆积和电子结构之间关系的新见解，为优异分子半导体提供了思路。
